一氧化氮参与钾胁迫对烟草根系生长的影响
时间:2018-10-26 11:45 来源:毕业论文 作者:毕业论文 点击:次
| 摘要:钾离子是一种植物生长中的主要限制因素，我国主要农作物普遍遭受着低钾胁迫的影响。而 一氧化氮（NO）作为一种植物根系对环境适应的一种信号分子,在低钾胁迫下是否参与根系生长的调控并不清楚。本文以两个在低钾胁迫下生长差异明显的烟草品种为研究对象，研究了正常和低钾处理下烟草根系的一氧化氮积累和硝酸还原酶（NR）活性的变化，在此基础上研究了NO供体（SNP）和NO清除剂（cPTIO）、NR抑制剂和NO抑制剂合酶(L-NAME)的添加对烟草根系的生长。与对照处理相比，低钾处理14天时，低钾耐受品种NC89的生长变化不显著；但低钾敏感品种云烟一号根系生长显著被抑制，进一步研究表明低钾胁迫条件下云烟1号根系生长被抑制主要表现为一级侧根的发生和伸长被显著抑制。与对照处理相比，低钾处理下仅1天根尖分生区就出现NO的显著积累，但NC89的根尖并未出现NO积累。在低钾胁迫的早期，NO的产生途径是NR途径。NO供体（SNP）使一级次根长度减少的程度在对照组和低钾处理的云烟1号中类似。然而cPTIO和L-NAME外源处理的结果则相反。29690 毕业论文关键字：延伸次根 NO 钾缺乏烟草 目录 摘要1 关键词1 Abstract1 Key words1 1.简介1 2.材料和测定方法2 2.2.1植物生长3 2.2.2根系结构记录4 2.2.3钾浓度测定4 2.2.4根尖NO含量的测定4 2.2.5硝酸还原酶（NR）活性测定4 2.2.6 qRT-PCR分析4 2.2.7数据分析5 3.结果5 3.3.1两个品种烟草对钾缺乏的反应的不同5 3.3.2缺钾抑制云烟一号的一级侧根的生长和延长7 3.3.3缺钾使云烟1号中NO含量增加，而NC89则不增加7 3.3.4低钾情况下通过硝酸还原酶途径诱导NO含量增加8 3.3.5外源添加NO供体和NO清除剂影响一级侧根伸长9 3.3.6生长素介导产生的NO也可以在缺钾下抑制一级侧根伸长10 4.讨论11 5.参考文献12 一氧化氮参与钾胁迫对烟草根系生长影响 Abstract：Potassium (K+) is a major limiting element of plant growth, and crops often suffer from low-K+ (LK) stress. Although nitric oxide (NO) is a signaling molecule involved in plant root adaptation to the environment, it remains unclear whether it participates root growth regulated by LK conditions. Two tobacco cultivars (Nicotiana tabacum L.) exhibiting variant growth features under LK were used in this study. We investigate the effects of LK on root growth, NO-accumulation, nitrate-reductase (NR) activity and effects of NO-donor (SNP), NO-scavenger (cPTIO), NR-inhibitor (tungstate), and NO-synthase-inhibitor (L-NAME) on elongation of first-order lateral-root (LR). Compared with control-treatment, LK-tolerant cultivar NC89 maintained plant growth under LK at 14 days, while dry weight was reduced significantly in LK-susceptible cultivar Yunyan1. Low-K+-inhibited root growth, mostly by impairing first-order LR’sformation and elongation, was only recorded in cv. Yunyan1. NO accumulation increased in root tips even when cv. Yunyan1 subjected to LK at day 1. LK-induced NO was generated by NR-pathway during early LK. SNP-application to control-treated plants decreased first-order LR elongation to levels similar to LK-treatment in cv. Yunyan1, while cPTIO, L-NAME, and application had the opposite effect. Further results suggested that NO might be involved in auxin-mediated LR elongating as plants responding to LK. In conclusion, NO generated by NR pathway may be involved in the inhibition by LK-stress of first-order LR elongation in tobacco plants. Key words:elongation;LR;NO;LK;tobacco 1. 简介 钾离子是植物生长发育中一种必需营养物质。可以占到植物干重的10%以上，而且是植物细胞中最重要的阳离子。然而，土壤中的钾离子浓度在0.025–5.0 mM，但是在根际中，浓度一般小于0.3 m[1]。即使在肥沃的土壤中，钾离子的可利用性也和环境条件有关，比如说土壤湿度和土壤密度[2]。所以说。植物可能经常性经历钾离子缺乏的情况。 (责任编辑：qin) |